Conventionally, there is widely used biometric authentication for authenticating an individual by using biometric information (for example, fingerprint, palm vein pattern, and iris of the eye) that is information specific to the individual and is hard to be forged.
For example, in entry control into a facility by using biometric authentication, only if biometric information accepted from a person desiring to enter the facility matches biometric information previously registered as a user, the person desiring to enter the facility is authenticated as the user who is permitted to enter the facility, and so the person is permitted to enter the facility.
Here, a method for biometric authentication is roughly classified into two types: “1:1 authentication” and “1:N authentication”. The “1:1 authentication” is implemented by accepting identification information such as ID together with biometric information from a person requesting authentication (for example, a person desiring to enter the facility), identifying the biometric information corresponding to the identification information from previously registered biometric information, and matching the identified biometric information against the accepted biometric information, to authenticate whether the person is an authenticated user. The “1:N authentication” is implemented by accepting only biometric information from a person requesting authentication, and matching the accepted biometric information against a plurality of previously registered biometric information (all or some of information as objects for matching), to authenticate whether the person is an authenticated user.
As seen above, because the “1:N authentication” does not require identification information such as ID (for example, the user is not required to carry an ID card or the like capable of storing therein and transmitting the identification information), this method is gaining attention as a method excellent in convenience as compared with the “1:1 authentication”.
However, the “1:N authentication” has a problem that the time required for a matching process with the accepted biometric information is increased with an increase in the number (N) of biometric information as objects for matching.
Japanese Laid-open Patent Publication No. 2002-140707, therefore, discloses a priority processing unit that focuses on information in which a certain tendency appears in a behavior pattern of each individual such as a start of office hours of each employee, adds, for example, each priority according to time slots to registered biometric information, and matches biometric information accepted in a certain time slot against those in order from biometric information with a high priority that is added thereto according to the time slot, among the registered biometric information, to reduce the time required for the matching process.
Japanese Laid-open Patent Publication No. 2003-44442 discloses a data authentication method for reducing a time required for a matching process in such a manner that when a server holding therein biometric information for all registered users accepts the biometric information for a user through a terminal owned by the user, and matches the accepted biometric information against the biometric information for all the registered users, to authenticate an access from the terminal, the server downloads the biometric information for the user held thereby into a cache memory of the terminal, and performs subsequent authentication by using the biometric information downloaded into the cache memory of the terminal.
Japanese Laid-open Patent Publication No. 2001-167305 discloses a gate management system for reducing a time required for a matching process by storing information for a person on a blacklist and information for a person who frequently passes a gate, from a server to a cache memory of the gate.
A technology for matching in order from the biometric information with a high priority has a problem that efficient authentication cannot be always achieved because only one behavior pattern is focused on and a priority is added thereto.
More specifically, the behavior pattern of each individual is not limited by only one element, but changes according to a plurality of elements such as a change of a time slot, a day of the week, and working hours. Therefore, there is a problem that even if only the one behavior pattern is focused on and the priority is added thereto, the efficient authentication cannot be always achieved.
The technologies using the cache memory have a problem that because the biometric information is cached based on previously determined information, the technologies cannot support the behavior pattern of each individual that changes according to the plurality of elements, and thus the efficient authentication cannot be always achieved.